<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    html,
    body {
      width: 100%;
      height: 100%;
    }

    body {
      background-color: pink;
      display: flex;
      flex-direction: row;
      align-items: center;
      justify-content: center;

    }

    .heart {
      width: 200px;
      height: 200px;
      background-color: red;
      position: relative;
      transform: rotate(45deg);
      box-shadow: 0 0 30px red;
      animation: heartbit 1s alternate infinite;
    }

    .heart::before {
      content: "";
      width: 200px;
      height: 99px;
      background-color: red;
      position: absolute;
      left: 0;
      top: -99px;
      border-radius: 100px 100px 0 0;
      box-shadow: 0 0 30px red;
    }

    .heart::after {
      content: "";
      width: 99px;
      height: 200px;
      background-color: red;
      position: absolute;
      left: -99px;
      top: 0px;
      border-radius: 100px 0 0 100px;
      box-shadow: 0 0 30px red;
    }

    @keyframes heartbit {
      0% {
        transform: rotate(45deg) scale(0.9)
      }

      100% {
        transform: rotate(45deg) scale(1.2)
      }
    }
  </style>
</head>

<body>
  <div class="heart">

  </div>
</body>

</html>